bug#2648: 23.0.60; remove C-c ` from rcirc track minor mode

[Stefan Monnier]

> rcirc track mode defines the following keys.

> (define-key rcirc-track-minor-mode-map (kbd "C-c `") 
> 'rcirc-next-active-buffer)
> (define-key rcirc-track-minor-mode-map (kbd "C-c C-@") 
> 'rcirc-next-active-buffer)
> (define-key rcirc-track-minor-mode-map (kbd "C-c C-SPC") 
> 'rcirc-next-active-buffer)

> When this mode is enabled, those keys become GLOBAL and therefore can
> easily step on bindings from other packages. One of them is AUCTeX.

> I think it is entirely redundant to bind 'C-c `'. I'd propose this key
> be removed when emacs is released. Otherwise it will confuse AUCTeX
> users. Whenever there's an error, AUCTeX will ask users to type C-c ` to
> get to the error, but instead this key will run
> rcirc-next-active-buffer.

The Elisp manual says:

      The key sequences bound in a minor mode should consist of `C-c'
   followed by one of `.,/?`'"[]\|~!#$%^&*()-_+='.  (The other punctuation
   characters are reserved for major modes.)

So, I think only the C-c ` binding should stay and the others should
be removed.  As for the conflict with AUCTeX, I'm not sure what we
should do.  Maybe use some other key.  Arguably, buffer-local minor
modes should take precedence over global minor modes, in which case
AUCTeX's C-c ` binding would take precedence, but this is a "TODO"
feature, so it doesn't help us here.


        Stefan